This member is working on Project A and Project B. Select "Main Project" in the project navigator. The Effort completed in both projects displays in the Effort Quicklist report (as long as the Single Level Project View filter is not selected).

Main Project <--Select this projectProject AChild AProject BChild B

To include both open and closed sprints/iterations, select the Show Closed Sprints (or Closed Iterations)check box and leave the Sprint (or Iteration) filter set to All.